Anyone ever get failed for to many wires in a drilled hole?

[Pierre C Belarge]

I thought NM was to be rated per the 60-deg column.

14 = 20a
12 = 25a

I would say this portion of the NEC (334.80) would affect the ampacity of a conductor for 240.4(G).
Although 240.4(D) restricts standard fusing size, such as 15A - for 14 AWG, 240.4(G) would permit in some installations to increase the size of the OCPD, which would be greater than 15A- for 14 AWG.
But, 334.80 will restrict the use of NM to no greater rating than the 60C column, regardless of 240.4(G).

 

[Ohmy]

Around here, the inspectors say no more than 3.

 

[mivey]

Around here, the inspectors say no more than 3.

Sounds like a good number. I mean if you are just going to pull one out of the air.

 

[mcclary's electrical]

Around here, the inspectors say no more than 3.

That's funny,,,because there is no limit on the number, rather the ampacity of the conductors after derating applies

 

[LarryFine]

I've often thought (and occasionally mentioned here) that the same number of cables or conductors can be loaded very differently.

Several switch legs on a single circuit won't create anywhere near as much heat as the same number of wires supplying separate circuits.

 

[jaylectricity]

I've often thought (and occasionally mentioned here) that the same number of cables or conductors can be loaded very differently.

Several switch legs on a single circuit won't create anywhere near as much heat as the same number of wires supplying separate circuits.

So if your hole includes a feed in, feed out, and switched lighting load, you could probably add a cable from another circuit without too much problem?

Also, what size holes are we talking about?

 

[LarryFine]

So if your hole includes a feed in, feed out, and switched lighting load, you could probably add a cable from another circuit without too much problem?

I'm comparing, say, four 12-2 home runs, each carrying 16a worth of base-board heaters, to, say, four 12-2's entering a 3-gang switch box, one feed and three switch legs, on one circuit.

There will be an obvious difference in the heat created by each of the two examples. The former would be four circuits' worth of current simultaneously vs. the latter's single circuit's worth.

Also, what size holes are we talking about?

I guess the typical 7/8" or 1" auger-bored hole in wood framing is a good starting point. Four 12-2 NM cables would fit such a hole with no problem, and be eight CCC's in either case.

 

[Power Tech]

I'm comparing, say, four 12-2 home runs, each carrying 16a worth of base-board heaters, to, say, four 12-2's entering a 3-gang switch box, one feed and three switch legs, on one circuit.

There will be an obvious difference in the heat created by each of the two examples. The former would be four circuits' worth of current simultaneously vs. the latter's single circuit's worth.

I guess the typical 7/8" or 1" auger-bored hole in wood framing is a good starting point. Four 12-2 NM cables would fit such a hole with no problem, and be eight CCC's in either case.

Everybody on this forum calls the bare wire the GEC. Do you count this as a conductor?

Is that 3 or 4 NM's?

 

[mcclary's electrical]

Everybody on this forum calls the bare wire the GEC. Do you count this as a conductor?

Is that 3 or 4 NM's?

The only bare GEC is at the service panel.
I assume you meant EGC, and as far as CCC's apply, No, you don't count the EGC, but you count it for box fill.

 

[LarryFine]

Everybody on this forum calls the bare wire the GEC. Do you count this as a conductor?

What Mac said.

Is that 3 or 4 NM's?

Four in my examples, for a total of 8 CCC's.

 

[K2500]

I contend that derating need not be automatically applied to any single hole, given that its depth is less than 24". Unless your wires are bundled again within 24" of the hole.

I guess that's a mute point, considering standard 16"/24"OC framing.

I dont do houses much(at all), but i figure pulling wire through a bored hole would follow the same rules as pulling wire through a conduit(long hole). Is the difference mentioned in the NEC?

 

[Pierre C Belarge]

I contend that derating need not be automatically applied to any single hole, given that its depth is less than 24". Unless your wires are bundled again within 24" of the hole.

I guess that's a mute point, considering standard 16"/24"OC framing.

I dont do houses much(at all), but i figure pulling wire through a bored hole would follow the same rules as pulling wire through a conduit(long hole). Is the difference mentioned in the NEC?

See 334.80.

 

[infinity]

I contend that derating need not be automatically applied to any single hole, given that its depth is less than 24". Unless your wires are bundled again within 24" of the hole.

I guess that's a mute point, considering standard 16"/24"OC framing.

I dont do houses much(at all), but i figure pulling wire through a bored hole would follow the same rules as pulling wire through a conduit(long hole). Is the difference mentioned in the NEC?

Once the hole is fire or draft stopped the 24" rule goes out the window. Inspectors who just make up a number like no more than 2 or 3 cables in a hole have no idea what they're doing. I could put 4-3 wire cables through a hole and still only have 8 CCC's.

 

[Power Tech]

The only bare GEC is at the service panel.
I assume you meant EGC, and as far as CCC's apply, No, you don't count the EGC, but you count it for box fill.

Thanks for clearing that up.

 

[K2500]

See 334.80.

Darn, and I really thought I was on to something.

Once the hole is fire or draft stopped the 24" rule goes out the window. Inspectors who just make up a number like no more than 2 or 3 cables in a hole have no idea what they're doing. I could put 4-3 wire cables through a hole and still only have 8 CCC's.

I was equally dismayed to see the exclusion of the exception to 310.15(A)(2). That was my next contention.

ART. 334

That article is bit more restrictive than I had thought.

 

[infinity]

I was equally dismayed to see the exclusion of the exception to 310.15(A)(2). That was my next contention.

It was still there in the 2005 when the draft stopped derating was added to the NEC. The 2008 eliminated it completely.

 

[Ohmy]

Sounds like a good number. I mean if you are just going to pull one out of the air.

Not all inspectors. To to be fair...some inspectors pull from their A$$

 

[ivsenroute]

We are still under the 2005 which states you have to derate whenever you have more than 2 NM cables run through a draft stopped hole.

Was this changed in 2008?

 

[infinity]

We are still under the 2005 which states you have to derate whenever you have more than 2 NM cables run through a draft stopped hole.

Was this changed in 2008?

The exception to 310.15(A)(2) was removed from being applicable to these installations in the 2008. In the 2005 the derating requirement was just about unenforceable due to that exception.

 

[radiopet]

Paul Abernathy will fail you at the drop of a hat for exceeding the fill of a fire stopped hole.

First, I only do special inspections anymore when I have the time as I was promoted up the chain and second we require all the holes to maintain the fireblocking in one and two family dwellings, not firestopping. We deal with firestopping in commercial applications and we do have some local requirements that govern this application as well. We do not look at the fill for the hole being drilled.....we do look for damage to the cable for trying to cram more cables in a hole thus damaging the cable's jacket....but thats about the department has time to concern themselves with at this point.

Secondly, I have never failed anyone whom follows the, state adopted building codes, NEC? and/or local requirements set forth by city council, the mayor and the city charter.

Have a nice day !

FYI- Here is a nice article on it : http://www.fomo.com/building-technologies/from-the-experts/fireblock-vs-firestop.aspx